Modified zirconium phosphates

ABSTRACT

A process for modifying various inorganic compounds defined by the formula: 
     
         M(OH).sub.z (HQO.sub.4).sub.2 -z/2.xH.sub.2 O 
    
     wherein M is a metal ion selected from Groups IVA and IVB of the Periodic Table of Elements, Q is an anion selected from Groups VA and VIB of the Periodic Table of Elements, z is any value from 0 to 2 and x is a number of from 0 to 8, by replacing a hydrogen in the inorganic compound with a metal cation. Suitable cations include those elements selected from Groups IA, IIA, IIIA, IVA, IB, IIB, IIIB including the lanthanide and activide series, IVB, VB, VIB, VIIB and VIII of the Periodic Table of Elements and ammonium. Thereafter, elevation of the temperature causes modification of the crystalline structure of the exchanged compound and provides various novel crystalline phases. Substitution of dissimilar metal cations for those present in the heat modified structure, with or without subsequent washing with acid, or washing out of the original metal cations, creates still other crystalline phases.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 494,579 filed Aug. 5, 1974 now U.S. Pat. No. 4,059,679 whichwas a continuation of U.S. patent application Ser. No. 132,569 filedApr. 8, 1971, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to novel inorganic crystalline structures andtheir method of preparation.

When solutions of certain metals such as those found in Groups IVA andIVB of the Periodic Table of the Elements are mixed with oxyanions ofelements found in Groups VA and VIB of the Periodic Table of Elements,amorphous gels having limited ion exchange characteristics areprecipitated. Certain of these gels have been converted intostoichiometric crystalline phases by refluxing in a solution of a strongacid. Among the crystalline phases prepared in this manner areα-zirconium phosphate (hereinafter designated α-ZrP); see U.S. Pat. No.3,416,884; and β and γ-zirconium phosphates (hereinafter designatedβ-ZrP and γ-ZrP, respectively), see Journal of Inorganic NuclearChemistry, 1968, Vol. 30, pages 2249-2258, Pergamon Press.

Such compounds have limited catalytic uses while exhibiting some degreeof zeolitic (absorption) characteristics and poor temperature stability.Thus, heating of such compounds, such as up to 100° C., removes thewater of hydration without destroying the interlayer structure of thecompounds. However, additional heating to higher temperatures causescondensation to occur with attendant breakdown in the crystallinestructure and the ultimate creation of amorphous substances generallylacking in both zeolitic and catalytic characteristics.

It has now been found that through preliminary displacement of areplaceable hydrogen ion in the inorganic crystalline structure by ametal cation, (hereinafter sometimes referred to as ion exchange), theaforementioned high temperature instability is eliminated. In thismanner, various structural changes can be accomplished in the inorganiccrystal lattice without ultimate destruction of the crystalline natureof the compound. More specifically, when crystalline compounds of theformula:

    M(OH).sub.z (HQO.sub.4).sub.2-z/2.xH.sub.2 O               (1)

wherein M is a metal ion, Q is an anion, z is any value from 0 to 2 andx is an integer of from 0 to 8, and preferably from 1-5, are reacted(neutralized) with a cation, the resulting compounds have been found toretain a definite crystalline structure even when subjected totemperatures in excess of that necessary to drive off the water ofhydration.

Typical metal ions intended to be included in the above-identifiedformula (1) as M are metal ions comprising elements selected from GroupsIVA and IVB of the Period Table of Elements are disclosed on pages 392and 393 of the Handbook of Chemistry and Physics, 35th Edition. Specificexamples of suitable metal ions include silicon, germanium, tin, lead,titanium, zirconium, cerium, thorium, and hafnium. With respect to theanions set forth as Q in the aforementioned formula (1), suitableelements include those found in Groups VA and VIB of the aforementionedperiodic Table of Elements. Typical examples of such materials includephosphorous, arsenic, antimony, bismuth, chromium, molybdenum andtungsten.

Although it sometimes happens that (HQO₄) groups are replaced byhydroxyl groups to form compounds as defined by equation (1), preferredstarting materials are free of hydroxyl groups, i.e., those where z is0, wherein the formula is

    M(HQO.sub.4).sub.2.xH.sub.2 O                              (2)

wherein M,Q and x have the definitions set forth above.

Although it is not intended that this invention be limited to anyspecific theoretical concept, it appears that replacing at least some ofthe replaceable hydrogen ions of the crystal lattice of the compounds ofequation (1) with metal cations produces compounds of the followingformula:

    M(OH).sub.z Y.sub.t.sup.m+ (QO.sub.4).sub.2-z/2.xH.sub.2 O (3)

wherein m+ is an integer corresponding to the charge of the cation Y, tis a number such that mt=2-z/2, M, Q, z and x have the aforementioneddefinitions and Y is selected from hydrogen, ammonium, cations such asthose found in Groups IA, IIA, IIIA, IVA, IB, IIB, IIIB including thelanthanide and actinide series, IVB, VB, VIB, VIIB, and VIII of theaforementioned Periodic Table of Elements, and mixtures thereof. Where Yis a mixture of cations, the term Y_(t) ^(m+) will be understood toinclude Y_(a) ^(m+) W_(b) ^(n+) wherein m+ is the charge of cation Y andn+ is the charge of dissimilar cation W so that am+nb equals 2-z/2 inequation (3). When b equals 0, equation (3) is applicable.

Again, with respect to preferred starting materials free of hydroxylgroups, formula (3) would be as follows:

    MY.sub.t'.sup.m+ (QO.sub.4).sub.2.xH.sub.2 O               (4)

wherein t' is a number such that mt'=2 and M, Y, Q, x and m are definedas set forth above.

Typical of the aforementioned cations are such elements as lithium,beryllium, sodium, magnesium, potassium, calcium, rubidium, strontium,titanium, cesium, maganese, molybdenum, barium, scandium, copper, zinc,chromium, aluminum, iron, cobalt, nickel, silicon, vanadium, lanthanumand actinium as well as the lanthanum and actinium series. Preferred aremetal cations selected from the group consisting of alkali metals andalkaline earth metals, and having atomic numbers of at least 3 but notmore than 20.

The aforementioned displacement reaction of this invention can beaccomplished either through dry ion exchange, aqueous ion exchange, orthrough liquid-solid exchange with liquids such as titanium or tintetrachloride or with metal salts dissolved in organic liquids. When theprocess employs dry ion exchange, it is not encumbered by thelimitations present with aqueous ion exchange. Thus, it has been foundthat both anhydrous and hydrated salts can react directly in the solidstate with the crystalline compounds defined by equations (1) and (2).

Thereafter, subsequent high temperature treatment of the exchangecrystalline structure represented by formulas (3) and (4) apparentlyonly releases the water of hydration from the ion exchange compounds.The condensation reaction (during which water would normally be splitout of the compound) is thereby eliminated. The resulting compounds havebeen found to have characteristics similar to that of a molecular sievematerial. Thus, depending upon the particular interlayer spacing,various cations can either be included or excluded. For this reason, ithas now been found possible, by using the novel crystalline structuresof this invention, to readily separate such molecules as water, amines,alcohols and the like from hydrocarbon solvents.

In still another aspect of the invention, it has been found that,depending upon the extent to which the initial ion exchange isaccomplished, and furthermore depending upon the intensity of the heattreatment of the resulting ion exchange compounds, a plurality of phasesof crystalline compounds can be produced, each having its own interlayerstructure and x-ray diffraction pattern. For example, by partialreplacement with one cation, followed by heat treatment to alter thestructure and subsequent replacement of the first cation with a seconddissimilar cation, various structures having properties not directlyattainable by initial ion exchange are produced. Still further, washingout of the cations following the heat treatment leads to additionalforms of crystalline compounds.

Summarizing the process of the present invention, the starting materialcan be any of the compounds encompassed by formula (1), above, whetherin their known crystalline forms or, as has been found possible withα-ZrP, in an amorphous gel form. The initial step involves an exchangeof metal cations for the replaceable hydrogen ions present in thesecompounds. It will be readily apparent to one skilled in this art thatthe exchange can be employed to replace all of the hydrogen ions presentor only a small percentage such as about 10 to 20 percent. If theneutralization reaction is accomplished in an aqueous solution, ionexchange may be less than complete, i.e., less than 100 percent oftheoretical exchange is accomplished. As a result, heating then producesmixtures of phases that appear to represent 1/2 (1 hydrogen replaced permolecule) and full exchange (both hydrogens exchanged in somemolecules). It has also been found that the most useful metal cationsfor aqueous ion exchange are those elements classified in Groups IA,IIA, IIB and VIIB of the Periodic Table of the Elements.

In another aspect, it will be appreciated that the extent of ionexchange (cation loading), can be varied from zero to full exchange bystarting either with the acid form or alternatively with the cation formand washing with an acid. Thereafter, the exchanged crystalline compoundis heat-treated, first to remove any water of hydration, and thereafterto form new crystalline phases. Once any of the new crystalline phasesare obtained, all or part of the first metal cation can be replaced witha second metal cation. For example, Li⁺ and Na⁺ forms of the exchangersare particularly useful for secondary replacement. Thereafter, any ofthe heat treated crystalline phases can be used as catalysts or ionexchange compounds. Furthermore, by washing out the cations used toretain the crystalline structure during the heat treatment, structureshaving highly desirable absorption characteristics (similar to molecularsieves) can be obtained.

By way of specific embodiment, the remainder of this disclosure isprimarily directed to procedures for producing and creating novelphases, through ion exchange and treating, of various compounds andparticularly crystalline zirconium phosphates (ZrP), such as prepared inthe aforementioned publications, and especially α-ZrP, as prepared inU.S. Pat. No. 3,416,884. It will be readily apparent to one skilled inthis art that the zirconium phosphates are merely representative of thecompounds that can be obtained with any of the other metal ions, anionsand metal cations set forth in formulas (1) and (2). For instance,Example IV E illustrates the modification of hydrated titaniumphosphate; Example IV B the stabilization of hydrated zirconium arsenatewhile Example III A illustrates the preparation of a hydrated zirconiumarsenate; and Example IIIB a hydrated tin phosphate.

To further illustrate the process of this invention, the followingexamples are provided. It should be understood that the details thereofare not to be regarded as limitations as they may be varied as will beappreciated by one skilled in this art.

EXAMPLE I Preparation of α, β and γ-ZrP

A. α-ZrP One hundred grams of zirconium phosphate gel obtained by theaddition of zirconyl chloride solution to orthophosphoric acid wasdispersed in 200 ml. of water by vigorous agitation. The resultantslurry was added to 1600 ml. of concentrated orthophosphoric acid. Thediluted slurry, which had a molarity of 13 with respect to phosphoricacid, was refluxed for one hour. A sample was then removed and the solidmatter of the sample was filtered off, washed to remove solubleimpurities, and dried below 100° C. with P₂ O₅. When examined by X-raydiffraction this solid matter was found to be highly crystalline.Refluxing of the rest of the slurry was continued for 24 hours andanother sample was taken. The solid material in the second sample showedthe same X-ray diffraction pattern as the first one. Analysis of theproduct showed ZrO₂, 40.8%, P₂ O₅, 46.6%, and H₂ O, 12.4%, correspondingto Zr(HPO₄)₂.H₂ O.

B. β-ZrP 100 ml of 10 M ZrOCl₂.8H₂ O was added dropwise to a constantlystirred, refluxing phosphate solution, which had been prepared bydissolving 2 moles (276 g) of NaH₂ PO₄.H₂ O in 200 ml of 3 M HCl. (Thelatter solution was heated to reflux temperature to effect completedissolution of the sodium dihydrogen phosphate in the hydrochloric acidat the concentration levels specified). The zirconium phosphate gel,which precipitated immediately, was refluxed in its mother liquor for 25hrs. The resulting crystalline zirconium phosphate was filtered off withsuction using a very retentive, acid hardened filter paper. It was thenwashed on the filter: first with 2 M hydrochloric acid to the removal ofsodium ion (several liters were required), then with 0.2 M phosphoricacid to the removal of chloride ion (about one liter was required), andfinally with several small volumes of distilled, deionized water. Theproduct was then very thoroughly dried at room temperature in anaspirator-evacuated vacuum dessicator over anhydrous calcium sulfate forseveral weeks. Analysis: Found for ZrO₂ --43.56%, P₂ O₅ --49.03% Loss onIgnition--7.41%. Calculated for Zr(HPO₄)₂ : ZrO₂ --43.72%; P₂ O₅--49.94%; Loss on Ignition, 6.34%.

C. γ-ZrP This hydrated form of β-Zirconium phosphate is obtained byrepeating the procedure of Example IB, but air-drying rather than vacuumdrying over a suitable drying agent such as P₂ O₅. Analysis: Found forZrO₂ --38.57%; P₂ O₅ --43.98%; H₂ O--17.5%. Calculated for Zr(HPO₄)₂.2H₂O: ZrO₂ --38.60%; P₂ O₅ --44.47%; H₂ O--16.93%.

Alternately, if β-Zirconium phosphate is contacted by water, it willabsorb water until the composition Zr(HPO₄)₂ .2H₂ O is obtained. TheX-ray diffraction patterns of α-ZrP, β-ZrP and γ-ZrP are compared in thefollowing Table I, and demonstrates that these separate and distinctphases have entirely different structures.

                  TABLE I                                                         ______________________________________                                        X-ray Powder Patterns of the                                                  Different Crystalline Phases of                                               Zirconium Phosphate                                                           α-ZrP β-ZrP     γ-ZrP                                        d (A): I/I.sub.o :                                                                            d (A):    I/I.sub.o                                                                            d (A):  I/I.sub.o                            ______________________________________                                        7.56   75       9.4       90     12.2    90                                   4.48   40       5.40      100    5.81     100                                 4.44   25       4.65      50     4.62    35                                   3.57   100      3.83      20     4.35    35                                   3.53   55       3.56      85     3.74    45                                   3.29   5        3.30      90     3.31    90                                   3.21   10       3.12      40     3.20    35                                   3.08   5        2.69      50     2.68    35                                   3.02   2        2.15      25     2.17    20                                   2.64   30                                                                     2.62   35                                                                     2.48   5                                                                      2.41   10                                                                     2.34   5                                                                      2.27   2                                                                      2.22   2                                                                      2.19   5                                                                      2.17   5                                                                      ______________________________________                                    

α-ZrP has a layered structure, the layers consisting of zirconium atomslying in a plane held together by phosphate groups above and below theplane. The layers are arranged relative to each other in a staggeredfashion such as to form Zeolitic cavities. Thus, α-ZrP exhibits sievingbehavior. Cesium and rubidium ions are not exchanged in acid solutionbut Na⁺, K⁺, and Li⁺ are exchanged under such conditions.

β-ZrP has the same layered structure as α-ZrP but the layers arearranged differently relative to each other. Instead of being staggeredthey are directly over one another. This produces larger cavities andion exchange behavior separate and distinct from that of α-ZrP. Onheating α-ZrP to 100° C. it loses a mole of water so that itscomposition becomes the same as that of β-ZrP. However, its X-raypattern remains unaltered (excpet for line broadening) indicating nochange in structure.

When β-ZrP comes in contact with water, sorption of 2 moles of watertakes place with concommitant increase in interlayer spacing. In thisrespect it behaves as a claylike substance. The resultant γ-phase is theone actually taking part in exchange reactions in aqueous solution andis able to sorb large ions such as Cs⁺, Rb⁺, Ba⁺⁺. However, a realdistinction can be made between the β- and γ-phases. The β-phase acts asa drying agent whereas the γ-phase does not.

EXAMPLE II Comparison of Adsorption Characteristics of β- and γ-Zrp.

A. Six grams of β-ZrP was placed inside the lower portion of adessicator. A sample of sodium oxalate which had been exposed tomoisture so that it contained 1-2% water was sealed inside thedessicator overnight. A portion of the oxalate was then weighed out,dissolved in dilute sulfuric acid (250 ml containing 12 ml acid) andtitrated with a standardized solution of potassium permanganate. Theweighed sample was shown to be 99.98% pure, and hence, essentially allits water had been removed by the β-ZrP. When the experiment wasrepeated using γ-ZrP as dessicant, the sample contained 98.91% sodiumoxalate and 1.09% H₂ O showing that γ-ZrP was ineffective in removingthe water.

B. 500 ml of benzene was shaken with 100 ml of water so as to saturateit with water. The benzene layer was then separated from the aqueouslayer in a separatory funnel. To the wet benzene was added 1 g of β-ZrPand the mixture shaken continuously for 1 hour in a stoppered bottle.The solid was then filtered off and x-rayed. Its x-ray pattern was thatof γ-ZrP showing that close to 0.12 g of water were removed from thebenzene.

C. Sodium and cesium ions are readily exchanged by γ-ZrP at roughly thesame pH and give a sharp endpoint at 3.53 meg/g of dry exchanger weighedas β-ZrP. This is equivalent to the exchange of 1 mole of cation for 1mole of hydrogen ion. The corresponding titration curves for α-ZrP areshown in FIG. 2. α-ZrP exchanges 2 moles of sodium ion but does notexchange cesium ion in acid solution. These results are a consequence ofthe structures as described earlier. γ-ZrP having a very open structureexchanges large as well as small cations but α-ZrP only exchanges ionswith a radius of less than 1.33 A.

These exchange properties can effectively be used to separate largeradioactive ions from various ion mixtures. For example, long lived Csand Ba isotopes can be separated from radioactive wastes as follows: Thewaste liquor is adjusted to a pH of 4-5. It is then passed over a columnof α-ZrP where all ions having a radius of 1.33 A or less are removed.The effluent is then passed over a suitable column of γ-ZrP to removecesium and barium ions.

When α-ZrP is heated to 100° C. it loses 1 mole of water but does notundergo a change in its X-ray diffraction pattern. Furthermore, its ionexchange capacity remains unchanged.

EXAMPLE III Preparation of Compounds Other than ZrP

A. Zirconium Arsenate To 0.2 mole of arsenic pentoxide dissolved in 300ml of concentrated nitric acid was added 0.1 mole of zirconyl nitrate,ZrO(NO₃)₂.4H₂ O, dissolved in 85 ml of concentrated nitric acid. Themixture was refluxed for 24 hours, cooled and the white crystallinesolid filtered off. It was then washed with a 1% As₂ O₅ solution 5 timesand finally twice with distilled water. The solid was then dried over P₂O₅ until it attained a constant weight. Analysis gave 31.30% of ZrO₂ and58.10% As₂ O₅ which corresponds to the formula Zr(HAsO₄)₂.H₂ O. Thex-ray diffraction pattern of these crystals showed that the compound isisomophous with α-ZrP. Therefore, it will hereinafter be characterizedas α-ZrAs.

B. Tin Phosphate 35 g of SnCl₄.5H₂ O was dissolved in 250 ml of waterand added to 250 ml of 3 M phosphoric acid with stirring. Then 0.8 MNaOH was added until a precipitate formed. The mixture was boiled andthe precipitate which formed was filtered off and added to 500 ml of 6 Mphosphoric acid and refluxed for 24 hours. The solid was filtered off,washed several times with distilled water and air dried overnight. Theproduct was essentially amorphous showing only a few indistinct peakswhen exposed to x-radiation. Analysis was close to the compositionSnO₂.P₂ O₅.4H₂ O. However, the water content tended to vary frompreparation to preparation.

EXAMPLE IV Stabilization of Inorganic Crystalline Compounds

A. α-ZrP with Sodium Ions

1. To 1.0 gram of α-ZrP is added 100 ml of 0.1 N NaCl, then 0.1 M NaOHis added in small increments while monitoring the pH. When 33.2 ml of0.1 M NaOH is added a first endpoint is reached, i.e., the replacementof 1 replaceable hydrogen ion. The composition of the solid at thispoint was found to be Zr(NaPO₄) (HPO₄).5H₂ O. This phase was designatedphase A (Na⁺.5H₂ O) and its composition was found to be 23.15% Zr,47.18% PO₄, 5.79% Na, 25.11% H₂ O (determined as loss of ignition).Calculated for Zr(NaPO₄) (HPO₄).5H₂ O: 23.28% Zr, 47.93% PO₄, 5.80% Na,25.00% H₂ O.

Phase A (Na⁺.5H₂ O) was heated at 110° C. for four hours whereupon itlost 22.93% (5 moles H₂ O) by weight and formed the anhydrous compoundZr(NaPO₄) (HPO₄) designated phase C (Na⁺). This compound was found to bestable to 200° C. and as such was useful as a catalyst up to this andsomewhat higher temperatures. Phase A (Na⁺.5H₂ O) was found to have aninterlayer spacing of 11.8 A, while phase C (Na⁺) exhibited aninterlayer spacing of 7.33 A.

2. To 1.00 g of α-ZrP is added 50 ml of 0.1 N NaCl solution and then66.4 ml of 0.100 N NaOH solution slowly and with stirring over an 8-hourperiod. The final mixture was stirred until no further change in pH wasobtained. This quantity is equivalent to the amount of NaOH required toachieve the second endpoint; replacement of both replaceable hydrogenions. The solid was then filtered off and allowed to achieve a constantweight at 52% relative humidity. Analysis gave 24.07% Zr, 12.04% Na,49.77% PO₄, 14.18% H₂ O. Calculated for Zr(NaPO₄)₂.3H₂ O: 24.13% Zr,12.03% Na, 49.69% PO₄, 14.14% H₂ O. This solid was designated phase D(2Na⁺.3H₂ O); interlayer spacing -9.83A. When phase D was heated at 165°C. for 4 hours it lost its water content to form Zr(NaPO₄)₂ designatedphase F(2Na⁺); interlayer spacing -8.38 A. This phase was useful as acatalyst up to temperatures of about 400° C. whereupon it converted to aform designated phase G(2Na⁺); interlayer spacing -7.63 A. This phasewas stable to 800° C. and useful as a catalyst from room temperature to750° C. since it was found not to revert to phase F on cooling. Heatingphase G to 800°-900° C. converts it to a form designated phase H(2Na⁺,interlayer spacing -7.60 A, which was found to be stable from 0°-900° C.and useful as a catalyst throughout that temperature range.

3. To 1.0 g of α-ZrP was added 50 ml 0.1 N NaCl as supportingelectrolyte. Then 8.3 ml of 0.10 N NaOH is added dropwise and stirreduntil the pH achieved a constant value (˜3). The solid was then filteredoff and an x-ray pattern of the wet solid taken. The pattern showed thepresence of approximately 25% phase A (Na⁺.5 H₂ O) and 75% unexchangedα-ZrP. On heating to 225° C. for 6 hours a totally new phase is obtainedrather than a mixture of dehydrated phase A and dehydrated α-ZrP, asshown by the x-ray diffraction pattern below.

    __________________________________________________________________________    X-ray powder pattern                                                          of a mixture of phase                                                         A(Na.sup.+ . 5H.sub.2 O)+α-ZrP heated to 125° C.                 __________________________________________________________________________    d (A)                                                                             6.95                                                                             4.64                                                                             3.88                                                                             3.83                                                                             2.78                                                                             2.75                                                                             2.68                                                                             2.49                                                                             2.20                                                                             2.19                                           I/I.sup.o                                                                         40 20 35 100                                                                              8  15 30 4  4  5                                              __________________________________________________________________________

When α-ZrP alone is heated to 125° C. it loses a mole of water but itsX-ray pattern remains relatively unchanged. Thus, the absence ofreflections due to α-ZrP or dehydrated phases of phase A indicates thatthe sodium ion has distributed itself statistically about the exchangesites and formed a single new phase. (A solid solution with Na⁺statistically distributed among the exchange sites.)

B. Stabilization of α-ZrAs with Sodium Ion To 1 g of crystalline α-ZrAswas added 50 ml of 0.1 N NaCl solution. Then 52 ml of 0.1N NaOH wasadded in 1 ml increments with constant stirring over a 10 hour period.The solid was then filtered off and dried at 60% relative humidity.Analysis gave 9.79% Na and 11.6% loss on ignition (to 500° C.) Requiredfor Zr(NaAsO₄)₂.3H₂ 0:9.81% Na and 11.50% H₂ O.

The X-ray pattern of this solid was isomorphous with that of thecorresponding phase D(2Na⁺.3H₂ O) of zirconium phosphate (α-ZrP). Thedehydration behavior of the sodium substituted zirconium arsenate wasvery similar to that of the phosphate. A monohydrate was obtained at100° C., and a water free phase at 175° C. [phase F (2Na⁺)]. The X-raypatterns of these phases were similar to those of phase E (2Na⁺.H₂ O)and phase F(2Na⁺) of the phosphate showing that the phases areisomorphous.

C. Stabilization of α-ZrP with Potassium Ions In a manner similar tothat set forth in Example IVA supra, for titration of α-ZrP with sodiumions, titration of α-ZrP with potassium ions leads to a stable two phasesystem. Up to 50% of the exchange is a phase designated phase A(K⁺.1H₂O), Zr(HPO₄) (KPO₄).1H₂ O, and with the rest being unexchanged α-ZrP.Beyond the half exchange point a second two phase region consisting ofvarying amounts of phase A and a phase designated phase B (2K⁺.3H₂ O)are obtained.

Phase A on standing in air or heating to 150° dehydrates and forms phaseB which is stable to 150°; see X-ray diffraction patterns in Table II.Phase D(2K⁺.3H₂ O) forms phase E(2K⁺.H₂ O) on heating at 35° C. andphase F (2K⁺) on heating to 150° C. Further heating to 800° forms phaseG (2K⁺); see X-ray diffraction patterns in Table III.

                  TABLE II                                                        ______________________________________                                        X-Ray Diffraction Patterns of Zr(KPO.sub.4) (HPO.sub.4) . 1H.sub.2 O          and its Dehydration Products                                                  Phase A        Phase B (dried at 80°)                                  d        I/I.sub.o d           I/I.sub.o                                      ______________________________________                                        8.04     100       7.63        40                                             4.64     10        5.37         5                                             4.51     40        4.62        40                                             4.23     70        4.21        35                                                                3.82        100                                                               3.48        15                                             3.63     40        3.16        25                                             3.22     65        3.05        15                                             2.89     10        3.02         5                                             2.72     15        2.83        20                                             2.63     15        2.66         8                                                                2.65        25                                                                2.61         7                                                                2.54         8                                                                2.52         8                                                                2.29         4                                                                2.16        15                                                                1.90         8                                             ______________________________________                                    

                  TABLE III                                                       ______________________________________                                        X-ray Diffraction Patterns of Fully Exchanged                                 Potassium Form of α-ZrP and its Dehydration Products                    ______________________________________                                                     Phase E       Phase G                                            Phase D      (35-75°)                                                                             (dried 800°)                                d (A)   I/I.sub.o                                                                              d        I/I.sub.o                                                                            d      I/I.sub.o                             ______________________________________                                        10.8    100      8.84     40     9.21   60                                    5.37     5       4.59     40     4.04   100                                   4.56    30       4.32     90     3.19   90                                    4.53    60       4.03     10     2.60   45                                    4.33    50       3.90     100    2.50    5                                    3.80    60       3.65     10     2.24    3                                    3.72     5       3.53     50     2.18   10                                    3.65    30       3.18     10     2.01   25                                    3.23     5       3.02     90     1.96   15                                    3.07    55       2.97     15     1.80    5                                    2.96    20       2.70     65     1.67   10                                    2.71    40       2.62     70     1.59    6                                    2.65    45       2.59     15     1.48    6                                    2.63    15       2.36     10                                                  2.40     5       2.18     20                                                  2.26    10       1.89     10                                                  2.09    10       1.77     10                                                  1.90     5                                                                    ______________________________________                                        Phase F                                                                       (100-260°)                                                             d       I/I.sub.o                                                             8.93    100                                                                   8.04    10                                                                    3.99    90                                                                    3.16    90                                                                    3.05     5                                                                    3.00     5                                                                    2.59    30                                                                    2.48     5                                                                    2.24     2                                                                    2.16     5                                                                    2.00    20                                                                    1.95    15                                                                    ______________________________________                                    

D. Stabilization of α-ZrP with Lithium Ions In a manner similar to thatset forth in Example IVA supra, for titration of α-ZrP with sodium ions,titration of α-ZrP with lithium ions leads to the formation of a twophase system. However, the two phases persist up to 66% of total lithiumexchange. This differs from the sodium and potassium systems where thetwo phase region extended only to 50% of exchange. The two phases arethe original α-ZrP and Zr(LiPO₄)₁.33 (HPO₄).sub..67 -4H₂ O. This latterphase was designated phase A (1.33Li⁺.4H₂ O) and its X-ray pattern isgiven in Table IV.

Beyond 66% of exchange another two phase region was obtained. The twophases being phase A(1.33li⁺.4H₂ O) and the fully exchangedZr(LiPO₄)₂.4H₂ O. This latter phase was designated phase F(2Li.4H₂ O)and its X-ray pattern is given in Table V. The analytical results forphase A and F are given below.

Analysis of Phase A(1.33Li⁺.4H₂ O): Found: Zr, 25.3%; PO₄, 50.5%, Li,2.64%; H₂ O (Loss of Ignition) 21.2%. Calculated for Zr(HPO₄).sub..67(LiPO₄)₁.33.4H₂ O: Zr, 25.3%; PO₄, 52.2%; Li, 2.55%; H₂ O, 21.4%.

Analysis of Phase F(2Li⁺.4H₂ O): Found: Zr, 25.2%; PO₄, 49.8%; Li,3.82%; H₂ O (loss of Ignition), 19.63%. Calculated for Zr(LiPO₄)₂.4H₂ O:Zr, 25.0%, PO₄, 51.5%; Li, 3.77%; H₂ O, 19.57%.

The dehydration behavior for phase A was found to be quite complicated.At least 4 phases other than phase A (1.33Li⁺.4H₂ O) hereinafterdesignated phases B, C, D and E, are involved.

The phases and their probable water content are listed below.

    ______________________________________                                        Interlayer d Spacing                                                                      Phase              H.sub.2 O/Li                                   ______________________________________                                        8.55 A      phase B (1.33Li.sup.+  . 3 . 3H.sub.2 O)                                                         3.5                                            7.30 A      phase C (1.33Li.sup.+  . 1 . 33H.sub.2 O)                                                        1.0                                            7.84 A      phase D (1.33Li.sup.+  . 0 . 67H.sub.2 O)                                                        0.5                                            7.00 A      phase E (1.33Li.sup.+  )                                                                         0                                              ______________________________________                                    

Their X-ray patterns are listed in Table IV.

Phase A(1.33Li⁺.4H₂ 0) loses water slowly in air at room temperature.After about 1 week, a mixture, consisting of about equal amounts ofphase A, B, C and D was obtained. The same result was obtained muchquicker over P₂ O₅.

Heating a sample of phase A at 50° C. brought about the changes shownbelow:

    ______________________________________                                        Heating Time  5 min.   10 min. 25 min.                                                                              45 min.                                 ______________________________________                                        Solid   phase A   40%      25%                                                phases  phase B   30%      25%   30%                                          present phase C   15%      25%   30%    50%                                           phase D   15%      25%   40%    50%                                   Obs. water content                                                                          16.7%    15.6%   13.0%  7.7%                                    Calc. water content                                                                         16.9%    14.4%   11.2%  7.7%                                    ______________________________________                                    

Two of the above phases were isolated in relatively pure form. Heatingphase A(1.33Li⁺.4H₂ O), or any of the above mixtures at 110° for 96hrs., produced almost pure phase D. It contained about 0.6 mole, (3.76%)of water and was assigned the formula Zr(LiPO₄)₁.33 (HPO₄).sub..67.67H₂O. The water content was 1/2 mole per lithium atom. Heating phaseD(1.33Li.67H₂ O) at 185° resulted in the loss of this 0.67 mole of waterand formation of anhydrous phase E(1.33Li⁺). Phase E(1.33Li⁺) wasconverted to phase J at 450°. Its X-ray diffraction pattern was found tobe the same as that obtained when the fully exchanged phase F is heatedto 600° C. (Table V). Condensation to LiZr₂ (PO₄)₃ occurred at 800° C.This latter phase was identified by comparison with the X-ray pattern ofNaZr₂ (PO₄)₃ with which it is isomorphous.

                  TABLE IV                                                        ______________________________________                                         Phases Formed by Dehydration of Lithium Phase A                              ______________________________________                                        Phase A(1.33Li.sup.+  ·                                                           Phase B(1.33Li.sup.+  ·                                                            Phase C(1.33Li ·                          4H.sub.2 O)  3.5H.sub.2 O) 1.33H.sub.2 O)                                     d       I/I.sub.o                                                                              d        I/I.sub.o                                                                            d      I/I.sub.o                             ______________________________________                                        10.1    100      8.55     100    7.30   50                                    5.05    10       4.21     60     5.49    5                                    4.56    10       4.05     30     4.51   85                                    4.35    5        3.87     10     4.01   10                                    4.21    5        3.73     10     3.62   70                                    4.11    12                       3.49   100                                   3.89    20                       3.24    5                                    3.66    5                        3.14    5                                    3.59    6                        2.70   15                                    3.55    8                        2.66   30                                    3.41    5                        2.57   10                                    3.30    10                       2.38    5                                    3.23    5                        2.17    5                                    3.10    10                       2.08    5                                    2.99    5                        1.85    5                                    2.83    5                                                                     2.71    5                                                                     10 more                                                                       1.94                                                                          ______________________________________                                        D(1.33Li.sup.+ ·  Phase A heated to                                  67H.sub.2 O  Phase E(1.33Li.sup.+)                                                                       800° C. LiZr.sub.2 (PO.sub. 4).sub.3        d       I/I.sub.o                                                                              d        I/I.sub.o                                                                            d      I/I.sub.0                             ______________________________________                                        7.84    100      7.02     60     6.39   45                                    4.35    5        4.53     40     6.28   15                                    4.24    5        3.78     40     4.55   100                                   3.23    5        3.68     100    4.48   15                                    3.01    5        3.38     10     4.44   30                                    2.73    5        2.94      5     4.40   35                                    2.03    5        2.85      7     4.37   30                                                     2.68     30     3.83   35                                                     2.49      5     3.79   35                                                     2.41     10     3.19   30                                                                     3.17   30                                                                     3.11   25                                                                     2.88   25                                                                     2.86   20                                                                     2.54   25                                                                     2.52   10                                    ______________________________________                                    

Phase F(2Li⁺.4H₂ O). This phase was found to undergo complicateddehydration behavior. The phases formed and their approximate watercontent are given below:

    ______________________________________                                                         Interlayer d Spacing                                         ______________________________________                                        Phase G(2Li.sup.+ . 2-3H.sub.2 O)                                                                8.80 A                                                     Phase H(2Li.sup.+ . 1H.sub.2 O)                                                                  7.87 A                                                     Phase I(2Li.sup.+) 7.05 A                                                     Phase J(2Li.sup.+) 6.24 A                                                     ______________________________________                                    

Phase F dehydrated slowly at room temperature losing about 1% water in 2hours time at a relative humidity of 60%. A proportionate amount ofphase G formed with this small water loss. However, on standing overCaSO₄ in a dessicator for 7 hours, 5.25% water was lost (1.06 moles) andcomplete conversion to phase G occurred. Water losses as high as 8.75%(1.77 moles) were observed (over P₂ O₅) with no phase change. Allowingphase F to stand for longer periods of time over P₂ O₅ resulted inmixtures of phase G and H(2Li⁺.H₂ O). The latter phase was obtained freeof other phases by heating phase F or G at 80° to 140° C. In one caseheating phase F at 80° C. for 60 hours resulted in a loss of 2.78 moleswater (13.6%). In another experiment phase F was kept at 110° for 6 dayswhereupon it lost 2.67 moles water (13.5%). Thus the product is close toa monohydrate or phase H(2Li⁺.H₂ O).

Heating phase H at 185° C. converted it to Phase I. Approximately 1 moleof water was lost in the process. However, any temperature in the range185°-370° C. can be used and all but traces of moisture are removed atthe higher temperatures. Thus, phase I is considered to be anhydrous.Finally, heating above 450° C. converted phase I to another anhydrousphase called phase J(2Li⁺). X-ray patterns for phase J(2Li⁺) prepared atboth 600° C. and 800° C. are given in Table V.

                  TABLE                                                           ______________________________________                                        X-ray Diffraction Patterns of Phase F(2Li . 4H.sub.2 O)                       and its Dehydration Products                                                  ______________________________________                                        Phase F      Phase G         Phase H(2Li.sup.+ ·                      (2Li.sup.+ · 4H.sub.2 O)                                                          (2Li.sup.+ · 2-3H.sub.2 O)                                                          H.sub.2 O)                                       d (A)  I/I.sub.o d (A)     I/I.sub.o                                                                             d (A) I/I.sub.o                            ______________________________________                                        10.0   100       8.80      100     7.87  100                                  5.01    4        4.40      45      4.46  40                                   4.67    5        3.59      95      4.33  20                                   4.53   20        3.57      95      3.63  50                                   4.23   12        3.21      20      2.59  55                                   3.81   40        2.64      20      3.53  40                                   3.41   30        2.61      20      3.23  10                                   3.03   30        2.42       5      2.73   7                                   2.67   30        2.21      20      2.68   8                                   2.48    4        2.13       5      2.57   7                                   2.42    4        2.04       8      2.55   7                                   2.10    8        2.00       8      2.40   5                                   2.00   10                                                                     1.90    8                                                                     1.70   10                                                                     ______________________________________                                                     Phase J(2Li.sup.+)                                               Phase I(2Li.sup.+)                                                                         at 600° C.                                                                             at 800° C.                                d (A)  I/I.sub.o  d        I/I.sub.o                                                                             d     I/I.sub.o                            ______________________________________                                        8.11    5        6.24      10      6.19  10                                   7.05   65        5.57       8      5.61  10                                   4.56   35                          4.46  20                                   4.35    5        4.41      100     4.41  100                                  4.03    5                          3.98  10                                   3.87   25        3.95      10      3.96  15                                   3.65   100                         3.82   5                                   3.26   10        3.78      30      3.76  15                                   3.16    5                          3.75  35                                   2.95   30                          3.73  30                                   2.75   10        3.59       5      3.57   5                                   2.42   15                          3.46   5                                   2.18   12        3.44       5      3.44   5                                   2.03    7        3.35       7      3.35  10                                                    3.14      30      3.14  20                                                    3.07      12      2.10  40                                                    3.03       5      3.04   5                                                    2.84      10      2.84   5                                                                      2.77   5                                                    2.74       7      2.75   8                                                    2.64       5                                                                  2.55      25      2.55  15                                                                      2.54  30                                                    2.20       5      2.20   5                                                    1.98      10      1.98   8                                                                      1.97  13                                                    1.96      10      1.96  15                                   ______________________________________                                    

E. Stabilization of TiP with Sodium Ions To 1 gram of titaniumphosphate, Ti(HPO₄)₂.H₂ O, is added 50 ml 0.1 N NaCl as supportingelectrolyte. Then 0.1 M NaOH (78 ml) is added in small increments (24hrs.) until the second end point is attained. The solid was thenfiltered off and dried at 60% relative humidity. The composition of thesolid was Ti(NaPO₄)₂.3H₂ O and its X-ray pattern shows that it isisomorphous with the corresponding zirconium compound. On dehydration itunderwent substantially the same phase transitions as the correspondingzirconium compound.

EXAMPLE V Preparation of New Synthetic Ion Exchange Materials

A. One gram of α-ZrP was slurried with 100 ml of 0.1 N NaCl and titratedto the second end point with 0.1 M NaOH. (66.4 ml). The solid was thenfiltered off and heated at 600° C. for 1 hour. The crystals, after thistreatment, exhibited the x-ray pattern of phase G (2Na⁺) in Table VI.The exchanged heat treated crystals were then washed with 0.5 M HCl toremove all the sodium ion. The x-ray pattern was then that of theoriginal α-ZrP showing that no permanent change in the crystal latticehad occurred. However, when the experiment was repeated and theexchanged crystals heated to 800°, a phase transformation occurred. Thenew phase gave the x-ray pattern of phase H (2Na⁺) in Table VI. Nowhowever, when the Na⁺ was removed from the heat treated structure bywashing with HCl, a new hydrogen containing phase was obtained. Itsx-ray pattern is given as No. 1 in Table VII.

The exchange reaction need not be carried to completion. If some of thehydrogen atoms are allowed to remain in the crystals, then, on heating,condensation occurs according to the equation: ##STR1##

This produces pyro-phosphate linkages statistically distributedthroughout the crystal. Thus, by controlling the amount of cationexchanged into the lattice, it is possible to control the amount ofcondensation and thereby the structure of the resultant ion exchangephase.

This method can be applied to all the synthetic materials set forthsupra.

    ______________________________________                                        EXAMPLE V                                                                     X-Ray Patterns of                                                             Sodium Exchanged α-ZrP                                                  Fully Exchanged                                                               Anhydrous Phases                                                              Temp. 600° C.                                                                           High temp. (800°)                                     Phase G (2 Na.sup.+)                                                                           Phase H (2 Na.sup.+)                                         d        I/I.sub.o   d           I/I.sub.o                                    ______________________________________                                        7.63     100         7.60        100                                          4.51     60          7.17         8                                           4.35     20          6.33         6                                           4.09     40          5.74         5                                           3.85     20          4.98         8                                           3.74     75          4.55        18                                           3.53     10          4.40        25                                           2.90     20          4.35        44                                           2.65     50          4.30        42                                           2.52     35          4.19        22                                                                4.05         3                                                                3.90        40                                                                3.86        55                                                                3.79        55                                                                3.65        22                                                                3.49        35                                                                3.39        30                                                                3.36        28                                                                3.31        31                                                                3.16        14                                                                2.95        14                                                                2.89        18                                                                2.88        35                                                                2.82        25                                                                2.64        55                                                                2.53        30                                           ______________________________________                                    

                  TABLE VII                                                       ______________________________________                                        New Ion Exchanger Prepared By                                                 Heat Treating Exchanged α-ZrP                                           Phase H Heated to 800° C.                                              Followed By Washing With HCl                                                  d                I/I.sub.o                                                    ______________________________________                                        7.73             100                                                          4.56             15                                                           4.48             15                                                           4.40             22                                                           4.27              5                                                           4.09             10                                                           3.82             25                                                           3.75             12                                                           3.58             10                                                           3.29              8                                                           3.24             10                                                           3.17              8                                                           2.88             10                                                           2.66             15                                                           2.64             25                                                           2.58             10                                                           2.55             10                                                           ______________________________________                                    

EXAMPLE VI Solid State Ion Exchange

A. With α-ZrP The following equation illustrates the solid-statereaction of a salt with crystalline compounds such as α-zirconiumphosphate:

    Zr(HPO.sub.4).sub.2.H.sub.2 O+2/aMX.sub.a ⃡ZrM.sub.2/a (PO.sub.4).sub.2 +aHX+H.sub.2 O

wherein M is a metal ion, X is an anion such as a halogen, and a is thevalence of M.

1. Lithium Ion--Anhydrous lithium chloride (0.2 moles) was groundtogether with crystalline α-ZrP (0.1 mole) at room temperature. The odorof HCl was detected and a small amount of Li⁺ exchanged solid formed. Onheating to 130° C. for 1 hour complete exchange occurred as evidenced bythe change in X-ray pattern. The product was identified as Zr(LiPO₄)₂.H₂O. This resembles phase H. (See Table VIII for identifying X-raypatterns).

2. Sodium Ion--Using NaCl at 125° C. a mixture of three partiallyexchanged phases was obtained. At 375° C. the product was found to bephase G, Zr(NaPO₄)₂.

3. Aluminum Ion--Anhydrous aluminum chloride was mixed with α-ZrPcrystals in the ratio of 2 moles aluminum to 3 moles of a α-ZrPexchanger. The mixture was heated at 125° C. for 1 hour to give theX-ray pattern in Table IX(a). This product appears to be a mixture oftwo exchanged phases with interlayer spacings of 8.04 A and 7.38 A,respectively. Continued heating at 125° produced the X-ray pattern inTable IX(b).

4. Copper (II) Chloride--Anhydrous copper (II) chloride (1.68 g) wasmixed with α-ZrP (3.77 g) at room temperature. The mole ratio is 1 to 1.If the reaction were CuCl₂ +Zr(HPO₄)₂.H₂ O⃡ZrCu(PO₄)₂ +2HCl+H₂ O then a20.9% loss in weight should occur. The results of heating this mixturewere as follows:

    ______________________________________                                                                           Interlayer                                                                    Spacing of                                        Time (hrs.)         Color   Product                                    Temp.  of heating                                                                              % wt. loss                                                                              of Product                                                                              (A)                                      ______________________________________                                        125°                                                                          24        4.9       Brown   7.41 + CuCl.sub.2                          200°                                                                          48        5.6       Green   7.41 + CuCl.sub.2                          260°                                                                          24        15.66     Blue    7.87                                       330°                                                                          12        20.8      Blue    7.87                                       ______________________________________                                    

The X-ray patterns are given in Table X. The product obtained at 330° C.is apparently ZrCu(PO₄)₂.

5. Utilizing a similar solid-state procedure, other salts gave thefollowing results:

    ______________________________________                                                           Time              Interlayer                               Salt    Temp. (°C.)                                                                       (hrs.)  Result    Dist. (A)                                ______________________________________                                        MnCl.sub.2                                                                            160°                                                                              12                7.41*                                    MnCl.sub.2                                                                            200°-400°                                                                  12      Two Phases                                                                              7.41 + 5.57                              FeCl.sub.3 .               Yellow colored                                     6H.sub.2 O                                                                            200°-400°                                                                  24      Solid     7.41                                     CoCl.sub.2                                                                            160°                                                                              48      Blue colored                                                                  Solid     7.41                                     CoCl.sub.2                                                                            375°                                                                              12      Purple                                                                        Solid     7.87                                     ZnCl.sub.2                                                                            370°                                                                              48      Grey                                                                          Solid     7.87 + 7.41                              SnBr.sub.2                                                                            200°                                                                              24      Partial                                                                       Reaction  7.41                                     NiCl.sub.2                                                                            110°-400°                                                                   8      Orange                                                                        Solid     7.41                                     Ce(NO.sub.3).sub.3                                                                    190°                                                                               6      Yellow                                                                        Solid     7.41                                     HgCl.sub.2                                                                            115°                                                                              48      Partial Reaction                                                                        7.41                                     ______________________________________                                         *The 7.41 A and the 7.87 A phases have variable metal content from            partially exchanged to fully exchanged. All of the 7.41 A patterns show       that the phases are isomorphous but not identical since the intensities       are different. The same was found to be true of the 7.87 phases.         

B. With SnP--3 g of the tin phosphate prepared as in IIIB, above, wasthoroughly mixed with 5 g of NaCl and pressed into a disk at 5000 PSI.The disk was heated at 100° for 4 hours, then 200° for 8 hours. At theend of this heating period the solid was cooled and excess NaCl removedby dissolving in water. The solid tin phosphate was found to contain2.9% Na on an anhydrous basis. This shows that roughly 22% of theexchangable hydrogen ion was replaced by sodium ion.

The above list is diverse enough to show that almost any cation can beexchanged by finding the proper solid. Amorphous gels appear to behavein a similar manner. That true exchange has occurred can be shown bywashing out the cation with dil. acid and recovering α-ZrP. It is alsopossible to pass gaseous HCl over the solid. The protons diffuse intoZrP and the cations form chloride salts on the surface of ZrP which maybe recovered by sublimation or solvent extraction and recrystallization.

                  TABLE VIII                                                      ______________________________________                                        X-Ray Diffraction Pattern of Zr(LiPO.sub.4).sub.2 · H.sub.2 O        d                I/I.sub.o                                                    ______________________________________                                        7.90             100                                                          4.77             5                                                            4.41             50                                                           4.29             25                                                           4.20             8                                                            3.60             65                                                           3.56             75                                                           3.50             60                                                           3.22             15                                                           3.09             5                                                            2.71             10                                                           2.66             8                                                            2.54             5                                                            2.40             5                                                            2.21             5                                                            2.15             5                                                            2.06             5                                                            2.01             5                                                            1.99             5                                                            ______________________________________                                    

                  TABLE IX                                                        ______________________________________                                        X-Ray Diffraction Patterns of Solid-State                                     Aluminum Exchanged ZrP                                                        a. Prepared at 125° (1hr)                                                               b. Prepared 130° (24hrs)                              d        I/I.sub. o  d           I/I.sub.o                                    ______________________________________                                        8.04     85          7.41        100                                          7.38     75          4.55        35                                           4.53     45          4.23        40                                           4.44     40          3.72        80                                           4.04     45          3.20        10                                           3.93     100         3.04         5                                           3.65     15          2.74         5                                           3.54     65          2.64        10                                           3.10     15          2.60         8                                           3.07     10          2.34        15                                           3.00     30          2.12         5                                           2.64     70          1.86         5                                           2.18      5                                                                   2.04      5                                                                   1.97      5                                                                   ______________________________________                                    

                  TABLE X                                                         ______________________________________                                        X-Ray Diffraction Patterns of Copper Exchanged ZrP                            Prepared at 200° (48 hrs)                                                               Prepared at 330° (12 hrs)                             d        I/I.sub.o   d           I/I.sub.o                                    ______________________________________                                        7.41     100         7.87        20                                           4.55     15          6.61        15                                           4.23      5          4.67        25                                           3.71     25          4.25        35                                           3.55     10          3.93        20                                           2.73      5          3.65        100                                          2.63     20          3.45        10                                           2.12      5          3.34         5                                                                3.19        10                                                                2.89        20                                                                2.76         5                                                                2.55        30                                                                2.53        20                                                                2.40         5                                                                2.32         5                                                                2.26        10                                                                2.21         5                                                                2.11        10                                                                1.97         8                                                                1.93         8                                                                1.83         8                                                                1.71         5                                           ______________________________________                                    

EXAMPLE VII Solid-State Ion Exchange Variations

Although it is possible to exchange polyvalent cations into zirconiumphosphate by the solid-state technique as in Example VIA, supra, it issometimes advantageous to first prepare the sodium, potassium or lithiumform by either the titration method or the solid-state technique andthen to replace the alkali metal by a polyvalent cation. This isillustrated by the following:

The lithium exchanged form of zirconium phosphate, Zr(LiPO₄)₂.H₂ O, wasprepared as in Example VIA1. One gram of this phase was then added to 50ml of a 0.5 M CuCl₂ solution filtered off and reimersed in 50 ml. of 0.5M CuCl₂. The lithium ion was completely replaced by Cu⁺⁺ to form ahydrated copper zirconium phosphate, ZrCu(PO₄)₂.XH₂ O. Its X-ray powderpattern is shown in Table XI. The same phase is formed when the 7.87phase (Table X) is immersed in water. On dehydration the 9.35 phasereverts to the 7.87 phase.

EXAMPLE VIII Replacement of one cation by another cation

To 1 g of phase D (2 Na⁺.3H₂ O) prepared as in Example IVA2 was added 50ml of a 0.5 M solution of MnCl₂. The mixture is stirred for one hour,filtered and dried over P₂ O₅. 22% of the original Na⁺ was found to havebeen replaced by Mn⁺⁺. Further treatment of this product by freshsolutions of MnCl₂ resulted in additional replacement of Na⁺ by Mn⁺⁺until all of the sodium ion was replaced by Mn⁺⁺.

EXAMPLE IX Ion Exchange in Non-Aqueous Media

In previous examples it has been illustrated that the exchanger phase isstabilized by replacement of hydrogen ion by metal cations either inaqueous solution or in the solid state. It is also possible toaccomplish the same end result by carrying out the ion exchange innon-aqueous solvent such as alcohols, ethers, esters, etc. In some casesthe resulting products are different than those obtained in aqueoussolution or by the solid exchange method. Thus, other novel compositionsuseful as catalysts are obtained.

A. Ethanol Media 16.2 g of FeCl₃ was added to 200 ml of dry ethanol.After the iron(III) chloride dissolved, α-ZrP (30 g) was added withstirring to the alcohol solution. The mixture was then refluxed for 12hours and the resultant solid filtered off. It was washed with ethanoland dried under vacuum at 50° C. The dried solid was orange brown incolor and contained 2.4% Fe. This represents a 20% replacement ofhydrogen ions by Fe⁺⁺⁺ ions. The amount of hydrogen ions replaced may befurther increased by filtering off the solid and adding a fresh solutionof FeCl₃ dissolved in alcohol. By such successive treatments it ispossible to incorporate close to the theoretical amount of Fe⁺⁺⁺ intothe exchanger i.e., 6.64 meq of cation per gram of α-ZrP. However, ithas been found to be more advantageous to use the ammonium exchangedform of α-ZrP which on treatment with FeCl₃ dissolved in alcohol nowreplaces almost 80 % of the ammonium ions as in the example below.

B. Ethanol Media 30 g of α-ZrP are added with stirring to a concentratedammonium hydroxide solution. This treatment brings about 100%replacement of H⁺ by NH₄ ⁺ as shown in the following equation:

    Zr(HPO.sub.4).sub.2.H.sub.2 O+2NH.sub.4 OH⃡Zr[(NH.sub.4)PO.sub.4 ].sub.2.H.sub.2 O+2H.sub.2 O

The solid is filtered off and dried over phosphorus pentoxide. The drysolid was then slurried with 100 ml of dry ethanol and added to asolution of 16.2 g FeCl₃ in 200 ml of dry ethanol. The mixture was thenrefluxed for twelve hours and the solid recovered by filtration. Thissolid was found to contain 7.7% Fe, 13% C₂ H₅ OH and 4.5% NH₄ ⁺. Thiscorresponds roughly to the formula Zr(Fe)_(1/2) (NH₄)_(1/2)(PO₄)_(1/2).C₂ H₅ OH. On heating to 250° the alcohol splits out and at350° ammonia splits leaving a product of composition Zr(Fe)_(1/2)(H_(1/2))(PO₄)₂.

In all of the foregoing examples the acid form of the ion exchanger hadthe formula M(HQO₄)₂.xH₂ O. However it sometimes happens, due tohydrolysis, that some of the (HQO₄) groups are replaced by hydroxylgroups to form compounds of composition M(OH)_(z) (HQO₄)_(2-z/2).xH₂ Owhere z varies from 0 to 2. Such compositions undergo exchange in thesame way as the parent compounds M(HQO₄).xH₂ O and thereby produceexchanged phases of composition M(OH)_(z) Y_(t) ^(m+) (QO₄)_(2-z/2).xH₂O. When z is small these phases have the same x-ray patterns as thecorresponding parent compounds with z=0. However when z approaches 2 thephases tend to become amorphous.

EXAMPLE X Preparation of α-ZrP containing hydroxyl groups

10 g of the α-ZrP prepared in Example IA was added to 500 ml of watermade slightly alkaline (pH=9) by addition of NaOH. This mixture wasboiled under reflux for 3 days, cooled and the solid recovered byfiltration. The solid was washed with 1 N HCl until free of sodium ionfollowed by washing with water until free of chloride ion. The solid wasthen dried 3 days over P₂ O₅ and analyzed. Found: 40.6% ZrO₂, 43.5% P₂O₅ and 15.0% Loss on ignition. Required for Zr(OH)₀.28 (HPO₄)₁.88 1.6 H₂O; 40.8% ZrO₂, 43.5% P₂ O₅, 15.8% total H₂ O. In the above formulaz=0.28. The X-ray powder pattern of the solid was substantially the sameas given in Table I for α-ZrP.

The partially hydrolyzed α-ZrP was exchanged with sodium ions in muchthe same manner as detailed in Example IVA. The phases obtained afterexchange gave X-ray patterns similar to those formed from α-ZrP. Onheating they behaved in the same way as described for the exchangephases of α-ZrP except that above 500° C. the partially hydrolyzedproduct split out substantially 0.14 moles of water due to thecondensation of 0.28 moles of hydroxyl groups present in the solid.

EXAMPLE XI Utility of Metal Substitute Phase

The metal substituted inorganic ion exchange phases described herein areuseful as catalysts. To illustrate this point the following examples areoffered.

A. 1 g of copper zirconium phosphate, ZrCu(PO₄)₂, prepared by thereaction of CuCl₂ with Zr(HPO₄)₂.H₂ O (α-ZrP) at 330° and having theX-ray pattern of the 7.87 phase in Table X was added to a slurry of 1 gof asbestos in 50 ml of water. The mixture was vigorously agitated andthen the water evaporated by heating at about 70° C. By this procedurethe copper zirconium phosphate particles were made to adhere to theasbestos fibers. The solid was then loosely packed into a U tube fittedwith gas inlet and outlet tubes. The U tube was placed into a furnace inthe verticle position and a mixture of air and carbon monoxide led intoa pre-heater to warm the gases and then into the U tube and passed overthe copper zirconium phosphate. The exit gases were passed into a gaschromatograph so that they could be identified. The results were givenbelow.

    ______________________________________                                        Temp.  Flow Rate  CO-Air Ratio                                                                              Products                                        ______________________________________                                        250°                                                                           8 ml/min  1-3         75% CO.sub.2 + 25% CO                           300°                                                                           8 ml/min   1-10       100% CO.sub.2                                   300°                                                                          12 ml/min  1-1         70% CO.sub.2 + 30% CO                           ______________________________________                                    

It is evident that the catalyst is effective in converting CO to CO₂.This reaction is important as it is often desirable to prevent CO (fromvarious combustion processes as in automobile exhausts) from escapinginto the air.

It is also desirable to prevent hydrocarbons in automobile exhaust gasesfrom escaping into the atmosphere. A particularly difficult hydrocarbonto oxidize is methane. However, when a 1-5 mixture of methane and airwas passed over the copper zirconium phosphate catalyst at 500° and 4ml/min 50% was converted to CO₂ and H₂ O. Thus, it is apparent that thiscatalyst will be effective in converting hydrocarbons, their partiallyoxidized derivatives such as alcohols and carboxilic acids and carbonmonoxide into harmless products such as CO₂ and H₂ O.

When α-ZrP was used instead of the Cu⁺⁺ substituted form, no oxidationwas observed to occur.

B. A major air polluter is sulfur dioxide. This product always resultsfrom the burning of coal or petroleum as these fuels contain varyingamounts of sulfur containing compounds. When a mixture of SO₂ and airwas passed over the copper zirconium phosphate catalyst, it wasconverted to sulfur trioxide as shown below.

    ______________________________________                                        Temp.  Flow Rate  SO.sub.2 -Air Ratio                                                                       Products                                        ______________________________________                                        300° C.                                                                        6 ml/min  1-5         50% SO.sub.3 + 50% SO.sub.2                     500° C.                                                                       10 ml/min  1-5         70% SO.sub.3 + 30% SO.sub.2                     ______________________________________                                    

The sulfur trioxide is easily condensed out of the gas stream anddissolved in water to form sulfuric acid which is a useful article ofcommerce.

C. When cobalt zirconium phosphate, ZrCO(PO₄)₂, was used in place of thecopper salt substantially the same result was obtained. Thus it isevident that a wide variety of metal substituted zirconium phosphates(and other inorganic ion exchangers) may be used as oxidation catalysts.

                  TABLE XI                                                        ______________________________________                                        Hydrated Copper Zirconium Phosphate                                           d                I/I.sub.o                                                    ______________________________________                                        9.35             35                                                           5.37             15                                                           4.72             60                                                           4.53             80                                                           4.37             90                                                           4.13             100                                                          3.89             15                                                           3.53             60                                                           3.28             20                                                           3.07             50                                                           2.78             25                                                           2.63             70                                                           ______________________________________                                    

EXAMPLE XII Separation of Ions by Solid-Solid Ion Exchange

Three grams (˜ 0.0178 moles) of cesium chloride and 0.85 g (˜ 0.02moles) of lithium chloride were dissolved in 50 ml of water. Thesolution was then evaporated to dryness so as to obtain an intimatemixture of the two salts. This salt mixture was then intimately mixedwith 5 g of α-ZrP crystals and heated to 125° for 5 hours followed byheating at 250° for 2 hours. Then, the cooled solid was extracted withwater to dissolve the unexchanged salts. These were recovered byevaporation to dryness and x-rayed. The x-ray pattern was that of CsClwith a trace of LiCl. The zirconium phosphate solid was found to contain0.13 g Li or 94% of the lithium in the original LiCl. Thus the lithiumwas effectively separated from the cesium.

This separation was the result of the zeolitic nature of α-ZrP [A.Clearfield and G. David Smith, Inorg. Chem. 8, 431 (1969]. The entranceways into the cavities are large enough to admit a spherical ion of 2.66A diameter into the cavity. Larger ions are excluded. Thus Li⁺ whosediameter is 1.20 A is readily admitted but Cs⁺ with a diameter of 3.38 Ais excluded. Although the openings into the cavities are not known forthe other compounds of the type M(HQO₄)₂.XH₂ O it is reasonable toexpect that they vary from compound to compound because of thedifferences in atomic radii of M and Q. Thus, the subject compoundsconstitute a series of ionic sieves whereby ions may be separated bytheir size differences as shown in the above example.

Although the foregoing invention has been described in some detail byway of illustration and example for purposes of clarity ofunderstanding, it is understood that certain changes and modificationsmay be practiced within the spirit of the invention as limited only bythe scope of the appended claims.

What is claimed is:
 1. A process for modifying the interlayer spacing ofan inorganic compound of the formula

    M(OH).sub.z (HQO.sub.4).sub.2-z/2.xS

to produce a product of the formula

    M(OH).sub.z Y.sub.t.sup.m+ (QO.sub.4).sub.2-z/2

wherein M is zirconium S is water or a non-aqueous solvent, Q isphosphorus z is a number from 0 to 2 including fractional values, x isan integer of from 0 to 8, Y is a cation of groups IA-IVA, IB-VIIB,VIII, including lanthanide and actinide series, or ammonium, mt is aninteger corresponding to the charge of a cation Y, and t is a numbersuch that mt equals 2-z/2, wherein at least 10 mole percent of saidinorganic compound is converted to said product; said method comprisingmixing said inorganic compound in finely divided dry form with a finallydivided solid salt of cation Y, which is other than M; andheating saidmixture at an elevated temperature for a time sufficient to incorporatesaid salt cation Y into said inorganic compound by displacing at leastsome of the replaceable hydrogen ions to produce said product andthereby modify the interlayer spacing while retaining the crystallinenature of the compound structure.
 2. A process in accordance with claim1 wherein said temperature elevation is in excess of 100° C.
 3. Aprocess in accordance with claim 1 wherein said mixing is preceded by apreliminary displacement with dissimilar cations.
 4. A process inaccordance with claim 3 wherein said temperature elevation is in excessof 100° C.
 5. A process according to claim 1, wherein Y is an alkalimetal.
 6. A process according to claim 1, wherein Y is an alkaline earthmetal.
 7. A product formed by the process of claim 1.